In the initial funding period (1992-6) we found that mothers of very low birthweight infants (VLBW;< 1500 grams) have depressed lymphocyte proliferation and lower levels of some immune cell subsets compared to mothers of term infants in the first four postpartal months. Additionally, mothers of VLBW infants have higher anxiety, and anxiety in the early postpartum, is related to depressed immune function. If increased stress (including anxiety) and depressed immune function are related to detrimental changes in maternal and infant health, nursing interventions to improve the health of mothers and their VLBW infants could be designed and tested. These interventions could include efforts to decrease maternal and infant exposure to infection or other actions directed toward improving immune function such as decreasing fatigue, improving nutrition and exercise, or using relaxation techniques. Although differences in health behaviors did not account for differences between mothers of term and VLBW infants in immune response in our ongoing work, these health behaviors might make an important independent contribution to differences in health outcomes for mothers and their VLBW babies. In this phase, three groups of subjects (mothers of VLBW infants, mothers of term infants, and nonpostpartal women) will be compared to determine if stress and the depressed immune response we have documented are related to health outcomes. We will control for levels of sex hormones which may have an independent influence on immune status. Stress will be measured by: anxiety (Multiple Affect Adjective Checklist), daily hassles (Daily Hassles Scale), and serum cortisol levels. Changes in immune profile will be determined by lymphocyte and monocyte subset analysis using flow cytometry. Immune function will be measured in a subset of mothers using the lymphocyte proliferative response to mitogens and antigen recall. Prolactin and estrogen levels will be measured using single antibody RIA. Adult health will be measured by the Monthly Health Review and maternal interview. Infant health will be measured by: maternal interview, chart review, growth, and development using the Bayley Scales of Infant Development. This study will provide information about postpartal immune status necessary in targeting prophylactic nursing interventions for both mothers and their VLBW infants.